GMPartsGiant.com offers the wholesale prices for genuine 2018 Chevrolet Express 2500 parts. Parts like Automatic Transmission 4-5-6 Clutch Assembly & Turbine Shaft are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 4 Cyl 2.8L Diesel, 6 Cyl 4.3L, 8 Cyl 6.0L, 8 Cyl 6.0L Flex. Model Code: 3/4 TON CARGO EXPRESS, 3/4 TON PASSENGER EXPRESS.